Fatigue Cracks Detection and Quantification in a Four-Story Building using a Nonlinear Index and Vibration Signals

Abstract

One common damage in civil structures is the fatigue crack, where its detection in an incipient stage is vital because it can prevent catastrophic failures. This work proposes a new non-linear index based on the combination of statistical indices, principal component analysis, and Mahalanobis distance for detecting and quantifying the level of severity of fatigue cracks in a four-story building subjected to forced excitations. To evaluate the proposed vibration-based Structural Health Monitoring (SHM), elements with different levels of fatigue cracks, which are generated artificially, are introduced into the building. They represent light, moderate, and severe damage, i.e., 25%, 50%, and 75% of loss in a cross-sectional area of a beam, respectively. Results show that the proposal can make a reliable evaluation of the building condition. It can be considered a methodology with low complexity, low computational load, and reduced processing time. These conditions allow obtaining an early diagnosis, generating timely assignments for maintenance processes.